stateful filtering, ppp dialup link, secure ?

[zakinthinos@freemail.gr]

hi

i was wondering if there are any obvious security
security concerns in the following script

the script is placed into /etc/ppp/ip-up
($PPP_LOCAL is the dynamic ip and $DNS{1,2}
is the address of the dns server)

iptables -F
iptables -X
iptables -Z


iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT DROP

iptables -A OUTPUT -m state --state NEW,ESTABLISHED,RELATED -s $PPP_LOCAL -j ACCEPT
iptables -A OUTPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -o lo -j ACCEPT


iptables -A INPUT -p udp -d $PPP_LOCAL -s $DNS1 --sport 53 -j ACCEPT
iptables -A INPUT -p udp -d $PPP_LOCAL -s $DNS2 --sport 53 -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -p tcp -d $PPP_LOCAL --dport 1024: -j ACCEPT
iptables -A INPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -i lo -j ACCEPT


iptables -A OUTPUT -j LOG --log-prefix " OUTPUT: " --log-level debug --log-uid
iptables -A INPUT -j LOG --log-prefix " INPUT: " --log-level debug --log-uid